Allen Mogul Loose Driver

[10 Wheeler Rob]

Time for a little sarcasm? It has been 5 weeks since the origional post, one could have procured a set of wheel castings and axle stock and made all new parts by now and be up and running on the track.

I personally would have loctited it with the bearing retainer grade, and checked it for running true. If if trueness was good enough, than I would have added a duchman oposite the keyway.

If i was concerned about it lasting, I would make new wheels and axle in the off season.

Best of luck getting it finshihed soon.

Rob

[Harold_V]

Time for a little sarcasm? It has been 5 weeks since the origional post, one could have procured a set of wheel castings and axle stock and made all new parts by now and be up and running on the track.

I personally would have loctited it with the bearing retainer grade, and checked it for running true. If if trueness was good enough, than I would have added a duchman oposite the keyway.

If i was concerned about it lasting, I would make new wheels and axle in the off season.

Best of luck getting it finshihed soon.

Rob

Heh!
One would hope that the OP would have made decisions before now, and was back on the track, happily steaming.

Do note that he is not the one prolonging this conversation.

I can't speak for the objective of others, but I try to share my years in the trade, so that others might benefit. The big question now becomes what experience one may have in a given application. There are some things that apply across the board---standards by which those of us who have learned from the school of hard knocks, what is and what is not reliable.

If, in the process of discussing a subject such as this, an individual cops an attitude in which they won't listen to reason, there's not much anyone can do. If they prefer to stick with their preconceived notions, so be it. However, without having an understanding of the reasons for the position one might choose, no one benefits. Thus the purpose of this ongoing exchange. Someone, somewhere, is going to benefit.

Harold

[Harold_V]

Good Morning Harold, I see your point, BUT you have that same problem on the thread also from the abuse from normal use.

The tread?
No, you don't. The amount of surface area in question when comparing the tread to the bore is much greater, and there's little reason for the tread to wear unevenly, but that's not true of the bore.

Im sorry Harold, I have first hand experience with my American just after two season of running, you would be amazed at the ware that was present when i shoed her.

Likely so, but you're taking a shortcut through what I said, which, indeed, changes the point. Please take note that I made mention of wear uniformly as opposed to selective degradation (which is the potential problem I have tried to address, and you appear to ignore). For you to imply that a wheel bore that was (assumed to be) sloppy, knurled, then run until it was sloppy again, to be reliable as a reference point, simply isn't a good idea. You can't justify it by telling me about wheel wear on the tread, which is to be expected. I have not refuted tread wear, and have addressed that issue in my response, previously. I made mention that unless the casting was irregular in density, that wear can be expected to be uniform, for more likely than the bore to have been worn uniformly when it is influenced by irregular power impulses, and is wallowing on a knurl. Seems to me one of them is more likely to wear irregularly than the other (destroying the hoped-for reference surface). I may be wrong.

Yes, I expect you did find wear. I've seen it personally, in particular from wheels run on bar stock, such as is the case at Shady Dell. In fact, I have personally witnessed wheels that have been worn beyond being useful (better than 3,000 actual miles, and made of cast iron, run, primarily, on bar stock rail).

The point you are conveniently overlooking (for what ever reason) is that there is little reason for such (tread) wear to create eccentricity. By sharp contrast, we have a hole which was (assumed to be) sloppy at the outset, was operated, then knurled to tighten the fit (which knurling does not do), then operated again, to the point of failure. How you might assume that the resulting bore would still be a *reliable* reference I do not understand, but to suggest to others that it is is not doing them any favors. My years of experience in the trade tell me that that is a mistake, although one may be fortunate and find it isn't. It's not worth the gamble, not when there are other methods that can, and most likely will, yield far more reliable results, for there's little reason to expect that the tread (not thread) has sustained irregular wear, as opposed to the bore, in which a knurled shaft has been wallowing.

I stand my ground. I would not recommend the bore be used as a reference, but it would be easy enough to verify that it may, or may not be, reliable. To assume it is could be a mistake, simply leading to yet more repair work.

In closing, I may not have a firm understanding of your point, as you make reference to a *thread*, while I have been discussing the tread. They are not one and the same. Do I not understand what you are discussing?

Harold

[10 Wheeler Rob]

Harold,

The origional poster had posted on Sept. 10, that he had not bored the driver yet for the repair, so that was lead to my post.

I do apreciate all of your advice very much and was in no way taking issue with it, was just adding my 2 cents worth.

Have a great day,

Rob

[cbrew]

We all have our different approaches and ideas.
and that is what makes this board very useful.
happy building all

[Fred_V]

i think this has been a healthy discussion. the ideas are all worth noting. what i see on wheel wear is that the tire wears near the flange and that the outer edge usually has minimal contact with the rail. chucking the wheel by the flange and centering it from the outer edge of the tire should make it run true. then check the bore to see where it is. proceed as needed from there and that is a judgement call. there are many ways to fix it depending on time and money to be thrown at it. as they say on the plans so often "builders choice".

[dnevil]

I also appreciate the discussion, it has given me lots of options to tackle this problem.

Let me answer some of the questions that came up in the discussion.

1. The loco is the one in my avatar.
2. I have not put many hours on the loco myself. I have run it at two meets since I purchased it last December. Bob, the finishing building, ran it for about a year before he sold it. I think he purchased a completed chassis running on air, so Bob did not machine the drivers and axles.
3. The tread on the driver does show some wear (perhaps 1/64"). There is about 1/4" of unworn area on the tread on the outside of the wheel (farthest from the flange).
4. I have not performed any machining on the wheel or axle yet. They have been removed from the frame.
5. There is some rotational play when the driver is placed on the axle with the key in place. It looks like 1 degree or less (have not measured yet). Surely this is a problem on newly machined wheelsets also. How does one squarely align new drivers on new axles when performing a press fit?

I'd like to get as much wear out of this axle and driver as I can. Otherwise I am looking at many hours cutting a new axle and driver. The meet season is resuming in Texas (we take 3 months off in the summer due to the heat), so I don't want to miss the rest of the season.

I'll make my decision soon regarding which path to take and will report the results back to this thread.

Thanks again to all who contributed.

Daris

[10 Wheeler Rob]

I had reduced/tapered the first 0.100" of the axle end to allow the axle to get started into the wheel bore nice and straightand this allowed me to place the key in the wheel and press axle into the wheel and key in one shot. This was using a straight key.

Measure the key width, some key stock is undersize, either as bougt or done by the machinist. If you check sources like McMaster-Carr they sell full dimension and reduced dimension key stock. If the builder used comon bar stock it is often a 0.001 or more undersize.

If you go the loctite assembly route, the loctite would tend to center the key like it dose the radial fit.

Rob

[Fred_V]

I had reduced/tapered the first 0.100" of the axle end to allow the axle to get started into the wheel bore nice and straightand this allowed me to place the key in the wheel and press axle into the wheel and key in one shot. This was using a straight key.

Measure the key width, some key stock is undersize, either as bougt or done by the machinist. If you check sources like McMaster-Carr they sell full dimension and reduced dimension key stock. If the builder used comon bar stock it is often a 0.001 or more undersize.

If you go the loctite assembly route, the loctite would tend to center the key like it dose the radial fit.

Rob

also when machining a key way in the axle or broaching the slot in the wheel it is hard to get a good tight fit for the key. i have found i have to make keys to fit. maybe from my procedure or slop in my equipment. either way the slots come out oversize.

[RET]

Hi Daris,

The following instructions are what I would recommend and are a little more detailed because you say you are a relative novice. Welcome to the society! Remember, there are always several ways to do a job and what you wind up doing will depend on what you feel comfortable with, your experience and the equipment you have.

I see from your post that you haven't touched the wheel yet. That's great. Also from your post, it seems the outside of the wheel tread isn't worn and that what wear there is, is concentrated at or near the flange. This would be normal. In that case, try chucking the wheel by the flange and indicating on the outside of the tread in both planes, radial and axial. If when you have it as good as you can get (within a thou or two) and it runs OK, then you can proceed to clean up the bore. Axial indication removes the wobble, radial indication makes it run true. Remember, do all of this using a 4 jaw chuck and you will have to switch back & forth between axial and radial several times to get it as good as you can. Also, remember that you don't have to tighten the chuck up a lot because you are working on the bore, not the periphery.

Once it runs true, you can see how far off the bore is. Personally, I wouldn't recommend a sleeve with a keyway in this service, the loads are too high unless you plan to loctite the assembly. Yes, Loctite is just a "glue" but it is a very good one and there is enough surface area to give it a very good chance of working. If you do want to use loctite, the clearances should be about the same as those required for plain bearings, perhaps others with more experience with loctite can comment on this. Before you make the sleeve, clean up the shaft so you know what dimensions you have to work with to make the sleeve.

You really need to check the dimensions as I said in my previous post, if they are to the level I said, you will have a very smooth running assembly, even if they aren't as good, the wheels will still go around, just not as freely. Even if all this is true, you still can have problems if the quartering is off.

The one thing I glossed over before is the keying. I haven't used this method myself, but obviously, many others have done it successfully. For instance, there is a long list of experienced keyway users on this forum.

In thinking about it there are several pitfalls you must consider to get the angular alignment (quartering) right. A"Dutch" key on assembly is easiest and should work just as well as a square key. The usual method is to cut keyways at 90 degrees in the shaft then broach keyways in the drivers, then press the wheels on. The errors can come in both the axle and the wheel preparation. Since the wheels face in opposite directions you can get errors even if they are stacked and broached together. Using a broaching fixture oriented on the crankpin could make this OK, especially if the wheels are placed back to back and broached together. Remember, you still have to keep track of left and right wheels. Errors can also creep in when cutting the axle keyways because any lateral errors get multiplied when you get out to the crankpin radius. Many builders make a quartering fixture to help with this task. It doesn't matter if the quartering is exactly at 90 degrees, what does matter is that all wheel assemblies are the same.

You might even consider making a quartering fixture to check the other wheelsets because you don't want this to happen again. I'm sure it wasn't put together with this much slop originally, so something must have been off enough to have caused the wear. One advantage of making the fixture is that you can use it to assemble the problem wheelset after you check the others.

I'm not sure if all this is going to help, but I've tried to be as clear as I can. Remember, nobody knows it all, not even me!

Best of luck.

Richard Trounce.

[gcarsen]

My 2 cents, or comments

In a Repair/Job shop enviorment
A brass key could be fitted into the keyway of the worn axle end, then that end welded back up for the length of the driver hub. probably by TIG, cleaner and better control with out overheating and warping the end of the shaft. and the steel weld will not stick to the brass. then that end put back in the lathe and returned to a clean new diameter,probably .030, or so larger
then the wheel set up and rebored for a press fit on the new diameter, keep tha same keyways and orientation, and they stay sized to each other.
downside, one bastard end size, and all bearings will have to be slid on and of the other side.
upside, no bushings working around, or adding to possible runout issues, clean new surfaces for proper press or glue fits.

as for setting up the wheel, I would use a 1.000 mandrel (or size that fits), clean up the id of the bore as well as you can, slide the mandrel in and set it as tight as you can by hand making sure it fits well not being affected by burs or dings, or such.
set it up as Harold states, then check on the runout of the mandrel as it should be ridding in any original points that are left. then compare the 2. they should be true to each other (indicating inside of a damaged hole will alwayse be trouble) if the mandrel fits cleanly and solidly, probably get the face of the tread perfect, and for radial runout focus on the mandrel if they differ by much,


again, different methods.

Grant

[Dick_Morris]

One can never have too many options when something needs to be repaired. Here's my two cents worth.

When I bored a drive wheel a few thousanths too big I opened it up so that the OD was about 1/8" outside of where the keyway would be. I didn't have to idicate it because it was still in the lathe. I used either a four jaw or face plate - I don't remember which. The face plate may be easier with an already machined wheel. Don't forget that it's an accepted practice to take a light skim across the face plate to ensure it is true and flat.

Using a piece of cast iron that had already been machined to a few thousanths smaller (per Loctite specs) than the planned bore and with about six center punch marks (two rows at 120 degres apart) to keep it centered and to make it a light push fit into the hole, I Loctited the plug in place. After giving it some time to cure, the plug was machined and the keyway broached as if it were part of the original casting. Making the plug so that it's OD is about 1/8" clear of the finished keyway made me more comfortable than having a keyway that was cut totally through the plug. The larger diameter also gives extra area for the Loctite joint. I haven't put it in service yet, but the fix is nearly invisible and I don't expect it to give any problems. Just to be safe, for this application I'd use the combination of Loctite and primer that the company says will give you the best strength.